Laser - page 5 - Creative Uses of CHDK - CHDK Forum


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Offline yvesson

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    • poll about some pics (not much serious) ^^
Re: Laser
« Reply #40 on: 10 / February / 2010, 11:35:59 »
Here is one more for you, I did it last summer too, but forgot to share it. I had better that a lighter, that time :


Re: Laser
« Reply #41 on: 28 / April / 2010, 00:56:58 »
Forum newbie here.

The laser/flash-light images are the same thing I do real time with fast scanners and a HeNe Laser.  Draw under computer control.  Neat stuff.  I spent years writing software for it.

With the slow shutters you can do things like that as well as appear several times in a picture by 'painting' your face with a flashlight.  In an open, dark, field (no background) and a manual flash, you can also have two of you holding hands, etc...and things like the yvesson pictures I see below.  Time exposure for light trails and flash for the stationary stuff.
There's also neat things you can do with multiple flashes.  Make a black cut-out of yourself. Put it next to you -flash.  Now trade places with our cutout - flash again...two of you.

Anyway.  Does anyone know why these cameras will not "see" a remote, flash triggered flash?  Bums me out completely.

It can not see the remote.  UNLESS I manually flash it during a long open shutter.

On this puppy, I initially thought that the camera closes the "shutter" immediately after the internal flash and before the slave can fire.   These must obviously be an electronic "shutter" on the CCD (or whatever image sensor they have)

I have a SD500 and when I found out about CHDK I thought that I would now be able to slow the shutter and get the slave to register just like the old X sync setting on SLRs.  SLRs would first fully open the shutter (usually at 1/60th), then trigger the high speed (strobe) flash.
However, when I override the shutter speed down to even 1 second, the slave fires, but the image doesn't show it (doesn't record any of its light)! 
The internal flash fires at the beginning of the 1 second, firing the salve, but the image has no record of the slave.  What the bleep is going on here??  Could it be that the shutter still closes right after the internal flash fires then opens again for the time exposure - just so slaves won't work?

I think I hid my email so if you HAVE an answer, please also respond to K9DCI  at
arrl  dot org.

I may have to do some experimental pictures, or set up a photo sensor on an o-scope to see, or even do some laser image photos to figure out if the shutter does this open-close-open see it I can figure this out.

73, Steve, K9DCI   USN (Vet) MOT (Ret) Ham (Yet)


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